CN104601069B - A kind of inductance parameters acquisition methods of permagnetic synchronous motor and system - Google Patents

Abstract

This application provides a kind of inductance parameters acquisition methods and system of permagnetic synchronous motor, first the method and system apply space vector of voltage to permagnetic synchronous motor, then the current parameters of permagnetic synchronous motor under the impact of this space vector of voltage is obtained, calculate the rotor-position of the rotor of permagnetic synchronous motor again according to this current parameters, calculate the inductance parameters of permagnetic synchronous motor according to this rotor-position.The inductance parameters acquisition methods provided due to the application and system do not rely on frequency converter voltage, but obtaining inductance by the relational expression of inductance and electric current, antijamming capability is strong, and identification process is stablized, identification result deviation is little, thus can obtain point-device inductance parameters.

Description

Method and system for acquiring inductance parameters of permanent magnet synchronous motor

Technical Field

The application relates to the technical field of motors, in particular to a method and a system for acquiring inductance parameters of a permanent magnet synchronous motor.

Background

In a vector control system, a current loop is a loop with the fastest response in a speed regulating system, the quality of the controller parameters of the current loop directly influences the performance of the whole speed regulating system, and according to a classical control theory method, the most direct influence on the parameters of the current controller is the stator resistance and the inductance of a motor. The stator resistance and the inductance of the motor are not constant in the operation process, the magnetic energy supplied by the resistance and the permanent magnet of the motor is changed due to the change of temperature, the inductance value is changed due to different degrees of magnetic saturation caused by current change under different operation conditions, the flux linkage is more saturated along with the change of the motor current, the inductance change is nonlinear, and the parameter of the inductance in a saturation area is difficult to accurately calculate in the design of the motor, so that the influence of the inductance in the saturation area on the control performance of the system is worse. Therefore, obtaining accurate inductance parameters is crucial to the performance of the permanent magnet transmission system, and accurate identification of the inductance parameters of the motor can directly determine the control performance of the current controller, so that the performance of the whole speed regulating system is affected.

Disclosure of Invention

In view of this, the present application provides a method and a system for obtaining inductance parameters of a permanent magnet synchronous motor, so as to obtain accurate inductance parameters of the permanent magnet synchronous motor.

In order to achieve the above object, the following solutions are proposed:

a method for acquiring inductance parameters of a permanent magnet synchronous motor comprises the following steps:

applying a voltage space vector to the permanent magnet synchronous motor;

acquiring current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector;

calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter;

and calculating inductance parameters of the permanent magnet synchronous motor according to the rotor position.

Preferably, the applying a voltage space vector to the permanent magnet synchronous motor includes:

and applying the voltage space vector to a stator coil of the permanent magnet synchronous motor by using a three-phase inverter.

Preferably, the calculating the inductance parameter of the permanent magnet synchronous motor according to the rotor position includes:

and calculating the inductance parameter according to the relation between the phase self-inductance and the rotor position of the permanent magnet synchronous motor and the rotor position.

Preferably, the permanent magnet synchronous motor is provided with a position sensor, and calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter includes:

and calculating the position of the rotor according to the current parameters of the three phases of the stator.

Preferably, the permanent magnet synchronous motor has no position sensor, and the calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter includes:

converting the rotor of the permanent magnet synchronous motor into 0 ℃ through direct current excitation, calculating the direct-axis inductance according to the current parameter after the rotor is stabilized, and taking the 0 ℃ as the position of the rotor;

and converting the rotor into 90 degrees through direct current excitation, calculating the quadrature axis inductance according to the current parameter after the rotor is stabilized, and taking the 90 degrees as the position of the rotor.

An inductance parameter acquisition system of a permanent magnet synchronous motor, comprising:

the voltage applying module is used for applying a voltage space vector to the permanent magnet synchronous motor;

the current parameter acquisition module is used for acquiring current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector;

the rotor position judging module is used for calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter;

and the inductance parameter calculation module is used for calculating the inductance parameter of the permanent magnet synchronous motor according to the position of the rotor.

Preferably, the voltage applying module includes:

a three-phase inverter for applying the voltage space vector to a stator coil of the permanent magnet synchronous motor.

Preferably, the inductance parameter calculation is used for calculating the inductance parameter according to a relation between a phase self-inductance of the permanent magnet synchronous motor and a rotor position and the rotor position.

Preferably, the permanent magnet synchronous motor is provided with a position sensor, and the rotor position determination module is configured to calculate the position of the rotor according to current parameters of three phases of the stator, respectively.

Preferably, the permanent magnet synchronous motor has no position sensor, and the rotor position determination module includes:

the excitation driving unit is used for converting the rotor of the permanent magnet synchronous motor into 0 degree through direct current excitation;

the first calculation unit is used for calculating the direct axis inductance according to the current parameter after the rotor is stabilized, and taking the 0 degree as the position of the rotor;

the excitation driving unit is also used for converting the rotor into 90 degrees through direct current excitation;

and the second calculation unit is used for calculating the quadrature axis inductance according to the current parameter after the rotor is stabilized, and taking the 90 degrees as the position of the rotor.

According to the technical scheme, the method and the system for acquiring the inductance parameter of the permanent magnet synchronous motor are characterized in that a voltage space vector is firstly applied to the permanent magnet synchronous motor, then a current parameter of the permanent magnet synchronous motor under the influence of the voltage space vector is acquired, then the rotor position of a rotor of the permanent magnet synchronous motor is calculated according to the current parameter, and the inductance parameter of the permanent magnet synchronous motor is calculated according to the rotor position. The inductance parameter obtaining method and the inductance parameter obtaining system provided by the application do not depend on the voltage of the frequency converter, the inductance is obtained through the relation between the inductance and the current, the anti-interference capacity is strong, the identification process is stable, and the identification result deviation is small, so that very accurate inductance parameters can be obtained.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of an inductance parameter obtaining method for a permanent magnet synchronous motor according to an embodiment of the present disclosure;

fig. 2a is a state diagram of a switching tube of an inverter provided by the present application;

fig. 2b is a state diagram of one state of the switching tubes of the inverter provided herein;

fig. 2c is a state diagram of another state of the switching tubes of the inverter provided herein;

FIG. 3a is a straight axis position view of a rotor provided herein;

FIG. 3b is a straight axis position view of another rotor provided herein;

fig. 4 is a diagram of the relationship between the inductance of the permanent magnet synchronous motor and the rotor position thereof.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Facility one

Fig. 1 is a flowchart of an inductance parameter obtaining method of a permanent magnet synchronous motor according to an embodiment of the present disclosure.

As shown in fig. 1, the method for obtaining inductance parameters of a permanent magnet synchronous motor provided in this embodiment includes the following steps:

s101: a voltage space vector is applied to the permanent magnet synchronous motor.

The voltage space vector is generated by a three-phase inverter and then output to a stator coil of the permanent magnet synchronous motor.

There are currently many ways to generate the space voltage vector u_sThe comparison main stream is formed by controlling the opening of an IGBT tube by directly utilizing an inverter, voltage vectors such as an A axis are alternately applied from the positive direction and the negative direction along the axis of an ABC winding respectively, and a 0-degree vector u can be applied_s1And 180 vector u_s4The inverter switching tube states are shown in fig. 2a and 2 b:

the resulting impulse voltage and current responses are shown in FIG. 2c, with a reverse vector u applied during time period I_s4Time is T₁Application of u within time II_s1Time is T₂＝2T₁(ii) a Within time IIIApplying a reverse vector u_s4Time T₃＝2T₁(ii) a Application of u within time period IV_s1Time T₄＝T₁. Therefore, the current waveform symmetry can be kept, the amplitude of current pulsation can be reduced, the average current in the whole time period is close to zero, the generated average torque is almost nonexistent, and the position of the rotor is kept unchanged.

S102: and acquiring the current parameters of the permanent magnet synchronous motor.

Namely, the current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector are obtained.

S103: and calculating the rotor position of the rotor according to the current parameters.

Some permanent magnet synchronous motors include position sensors and some do not, and the rotor position of the two permanent magnet synchronous motors needs to be acquired in different methods.

For a permanent magnet synchronous machine comprising a position sensor, the rotor position is obtained in the following way:

for phase a, opposite pulse vectors are injected, and the resulting information is simplified as follows:

${\mathrm{\Δi}}_A={\mathrm{\Δi}}_{s1}-{\mathrm{\Δi}}_{s4}=\frac{\left|u_s\right|}{L_d{L}_q}((L_d+L_q)-(L_d-L_q)\cos {2\mathrm{\θ}}_r)\mathrm{\Δt}$

for phase B, the opposite pulse vector is injected, and the following equation can be derived:

${\mathrm{\Δi}}_B=\frac{\left|u_s\right|}{L_d{L}_q}((L_d+L_q)-(L_d-L_q)\cos 2({\mathrm{\θ}}_r-\frac{4}{3}\mathrm{\π}))\mathrm{\Δt}$

for phase C, the opposite pulse vector is injected, and the following equation can be derived:

${\mathrm{\Δi}}_c=\frac{\left|u_s\right|}{L_d{L}_q}((L_d+L_q)-(L_d-L_q)\cos 2({\mathrm{\θ}}_r-\frac{2}{3}\mathrm{\π}))\mathrm{\Δt}$

therefore, the following derivation is made:

$\begin{array}{c}{\mathrm{\Δi}}_A-{\mathrm{\Δi}}_B=\frac{\left|u_s\right|}{L_d{L}_q}(L_d-L_q)(\cos 2({\mathrm{\θ}}_r-\frac{4}{3}\mathrm{\π})-\cos 2\left({\mathrm{\θ}}_r\right))\mathrm{\Δt}\\ \⇒\frac{1}{L_q}-\frac{1}{L_d}=\frac{{\mathrm{\Δi}}_A-{\mathrm{\Δi}}_B}{\left|u_s\right|(\cos 2({\mathrm{\θ}}_r-\frac{4}{3}\mathrm{\π})-\cos 2\left({\mathrm{\θ}}_r\right))\mathrm{\Δt}}\end{array}$

the following assumptions were made:

$M_1=\frac{{\mathrm{\Δi}}_A}{\left|u_s\right|\mathrm{\Δt}},M_2=\frac{{\mathrm{\Δi}}_A-{\mathrm{\Δi}}_B}{\left|u_s\right|(\cos 2({\mathrm{\θ}}_r-\frac{4}{3}\mathrm{\π})-\cos 2\left({\mathrm{\θ}}_r\right))\mathrm{\Δt}}$

the equation for inductance can be derived as follows:

$L_q=\frac{2}{M_1+M_2(1+\cos 2{\mathrm{\θ}}_r)}$

$L_d=\frac{2}{M_1+M_2(\cos {2\mathrm{\θ}}_r-1)}$

as can be seen from the above formula, position information is included therein, and therefore solving the equation can obtain the rotor position of the permanent magnet synchronous motor.

For a permanent magnet synchronous motor that does not include a position sensor, the relationship of inductance to current can be achieved in two processes.

1) Solving the relation between the direct-axis inductance and the direct-axis current:

if the angle of the rotor is changed to 0 by direct current excitation, i.e. the straight axis coincides with the stationary coordinate as shown in fig. 3 a.

After the rotor has stabilized, alternating voltage information is injected in phase a, i.e. the equation in can be simplified as follows:

${\mathrm{\Δi}}_A=\frac{\left|u_s\right|}{L_d{L}_q}\left({2L}_q\right)\mathrm{\Δt}\⇒L_d=\frac{2\left|u_s\right|\mathrm{\Δt}}{{\mathrm{\Δi}}_A}$

wherein Δ I is known from the coordinate change_d＝ΔI_ATherefore, it is possible to findWherein, Δ i_dIncluding instantaneous direct current information i_d1、i_d2、i_d3、i_d4Taking the mean value of current i_{d_ref}＝0.25(i_d1+i_d2+i_d3+i_d4) Thus, the direct axis inductance L can be obtained_dCurrent i along with straight axis_{d_ref}The relationship (2) of (c).

2) Solving the relation between quadrature axis inductance and quadrature axis current:

if the angle of the rotor is changed to 90 deg. by dc excitation, i.e. the relationship of the straight axis to the stationary coordinate is shown in figure 3b,

after the rotor has stabilized, alternating voltage information is injected in phase a, i.e. the equation in can be simplified as follows:

${\mathrm{\Δi}}_A=\frac{\left|u_s\right|}{L_d{L}_q}\left({2L}_d\right)\mathrm{\Δt}\⇒L_q=\frac{2\left|u_s\right|\mathrm{\Δt}}{{\mathrm{\Δi}}_A}$

wherein Δ i is known from the coordinate change_q＝-Δi_ATherefore, it is possible to findWherein, Δ i_qContains instantaneous quadrature-axis current information i_q1、i_q2、i_q3、i_q4Taking the mean value of current i_{q_ref}＝0.25(i_q1+i_q2+i_q3+i_q4) Thus, the quadrature axis inductance L can be obtained_qCurrent i following quadrature axis_{q_ref}The relationship (2) of (c).

The above relations all include rotor information of the rotor, and therefore the rotor information of the rotor can be obtained by solving the relations.

S104: and calculating inductance parameters of the permanent magnet synchronous motor according to the position of the rotor.

Neglecting stator, rotor cogging and core saturation effects, for salient pole permanent magnet synchronous machines, the self inductance of the stator windings and the mutual inductance between the stator windings vary at twice the frequency as the rotor rotates. When the winding axis of a certain phase is coincident with the rotor axis, the self-inductance of the phase is L_dWhen the rotor rotates pi-After 2 electrical angles, the phase self-inductance is superposed with the center line between the poles of the rotor, and the self-inductance is changed into L_qAnd when the rotor changes pi electrical angle, the self-inductance of the winding changes by one circle. Therefore, the phase self-inductance is related to the position as follows:

L_a(θ_r)＝L₀+L₂cos(2θ_r)

$L_b\left({\mathrm{\θ}}_r\right)=L_0+L_2\cos ({2\mathrm{\θ}}_r+\frac{2\mathrm{\π}}{3})$

$L_c\left({\mathrm{\θ}}_r\right)=L_0+L_2\cos ({2\mathrm{\θ}}_r+\frac{4\mathrm{\π}}{3})$

the mutual inductance of the phase inductances is as follows:

$M_{\mathrm{ab}}=M_{\mathrm{ba}}=-\frac{L_0}{2}-L_2\cos ({2\mathrm{\θ}}_r-\frac{2\mathrm{\π}}{3})$

$M_{\mathrm{bc}}=M_{\mathrm{cb}}=-\frac{L_0}{2}-L_2\cos \left({2\mathrm{\θ}}_r\right)$

$M_{\mathrm{ca}}=M_{\mathrm{ac}}=-\frac{L_0}{2}-L_2\cos ({2\mathrm{\θ}}_r+\frac{2\mathrm{\π}}{3})$

wherein, $L_0=\frac{L_d+L_q}{2},L_2=\frac{L_d-L_q}{2}.$

the inductance-position relationship diagram is shown in fig. 4, and it can be known from the diagram that when the rotor position is at 0 position or pi/2 angle, the values of the phase inductances are the orthogonal and the orthogonal axis inductances of the motor, respectively.

And obtaining the inductance parameter of the permanent magnet synchronous motor by using the relation between the inductance and the position and the rotor position obtained in the step.

According to the technical scheme, the method for acquiring the inductance parameter of the permanent magnet synchronous motor comprises the steps of firstly applying a voltage space vector to the permanent magnet synchronous motor, then acquiring a current parameter of the permanent magnet synchronous motor under the influence of the voltage space vector, then calculating the position of a rotor of the permanent magnet synchronous motor according to the current parameter, and calculating the inductance parameter of the permanent magnet synchronous motor according to the position of the rotor. The inductance parameter obtaining method provided by the application does not depend on the voltage of the frequency converter, the inductance is obtained through the relation between the inductance and the current, the anti-interference capability is strong, the identification process is stable, and the identification result deviation is small, so that very accurate inductance parameters can be obtained.

Example two

The embodiment is an inductance parameter acquisition system of a permanent magnet synchronous motor, and the system comprises a voltage applying module, a current parameter acquisition module, a rotor position judgment module and an inductance parameter calculation module.

The voltage applying module is used for applying a voltage space vector to the permanent magnet synchronous motor. Which includes a three-phase inverter for outputting voltage space vectors.

The current parameter acquisition module is used for acquiring current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector;

the rotor position judging module is used for calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter; if the permanent magnet synchronous motor is provided with a position sensor, the inductance parameter is calculated according to the current parameters of the three terms of the stator.

If the permanent magnet synchronous motor comprises a position sensor, the rotor position judging module comprises an excitation driving unit, a first calculating unit and a second calculating unit, wherein the excitation driving unit is used for converting the rotor of the permanent magnet synchronous motor into 0 degree through direct current excitation; the first calculation unit is used for calculating the direct-axis inductance according to the current parameters after the rotor is stabilized, and taking 0 degree as the position of the rotor; the excitation driving unit is also used for converting the rotor of the permanent magnet synchronous motor into 90 degrees through direct current excitation; and the second calculation unit is used for calculating quadrature axis inductance according to the current parameter after the rotor is stabilized, and taking 90 degrees as the position of the rotor.

And the inductance parameter calculation module is used for calculating the inductance parameter of the permanent magnet synchronous motor according to the relation between the rotor position and the inductance.

It can be seen from the foregoing technical solutions that, this embodiment provides an inductance parameter obtaining system of a permanent magnet synchronous motor, where the system includes a voltage applying module, a current parameter obtaining module, a rotor position determining module, and an inductance parameter calculating module. The voltage applying module is used for applying a voltage space vector to the permanent magnet synchronous motor, the current parameter acquiring module is used for acquiring a current parameter of the permanent magnet synchronous motor under the influence of the voltage space vector, the rotor position judging module is used for calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter, and the inductance parameter calculating module calculates the inductance parameter of the permanent magnet synchronous motor according to the rotor position. Because the inductance parameter acquisition system provided by the application does not depend on the voltage of the frequency converter, the inductance is obtained through the relational expression of the inductance and the current, the anti-interference capability is strong, the identification process is stable, and the identification result deviation is small, so that very accurate inductance parameters can be obtained.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. The method for acquiring the inductance parameter of the permanent magnet synchronous motor is characterized by comprising the following steps of:

applying a voltage space vector to the permanent magnet synchronous motor;

acquiring current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector;

calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter;

calculating inductance parameters of the permanent magnet synchronous motor according to the position of the rotor;

the permanent magnet synchronous motor is not provided with a position sensor, and the rotor position of the rotor of the permanent magnet synchronous motor is calculated according to the current parameter, and the method comprises the following steps:

converting the rotor of the permanent magnet synchronous motor into 0 ℃ through direct current excitation, calculating direct-axis inductance according to the current parameter after the rotor is stabilized, and taking the 0 ℃ as the position of the rotor;

and converting the rotor into 90 degrees through direct current excitation, calculating the quadrature axis inductance according to the current parameter after the rotor is stabilized, and taking the 90 degrees as the position of the rotor.

2. The inductance parameter obtaining method according to claim 1, wherein said applying a voltage space vector to said permanent magnet synchronous motor comprises:

and applying the voltage space vector to a stator coil of the permanent magnet synchronous motor by using a three-phase inverter.

3. The inductance parameter obtaining method according to claim 1, wherein the calculating the inductance parameter of the permanent magnet synchronous motor according to the rotor position includes:

and calculating the inductance parameter according to the relation between the phase self-inductance and the rotor position of the permanent magnet synchronous motor and the rotor position.

4. An inductance parameter acquisition system of a permanent magnet synchronous motor is characterized by comprising:

the voltage applying module is used for applying a voltage space vector to the permanent magnet synchronous motor;

the current parameter acquisition module is used for acquiring current parameters of the permanent magnet synchronous motor under the influence of the voltage space vector;

the rotor position judging module is used for calculating the rotor position of the rotor of the permanent magnet synchronous motor according to the current parameter;

the inductance parameter calculation module is used for calculating the inductance parameter of the permanent magnet synchronous motor according to the position of the rotor;

wherein the permanent magnet synchronous motor has no position sensor, and the rotor position determination module includes:

the excitation driving unit is used for converting the rotor of the permanent magnet synchronous motor into 0 degree through direct current excitation;

the first calculation unit is used for calculating the direct-axis inductance according to the current parameter after the rotor is stabilized, and taking the 0 degree as the position of the rotor;

the excitation driving unit is also used for converting the rotor into 90 degrees through direct current excitation;

and the second calculation unit is used for calculating the quadrature axis inductance according to the current parameter after the rotor is stabilized, and taking the 90 degrees as the position of the rotor.

5. The inductive parameter acquisition system of claim 4 wherein said voltage application module comprises:

a three-phase inverter for applying the voltage space vector to a stator coil of the permanent magnet synchronous motor.

6. The inductance parameter obtaining system according to claim 4, wherein the inductance parameter calculation is configured to calculate the inductance parameter based on a relation between a phase self-inductance and a rotor position of the permanent magnet synchronous motor and the rotor position.